1. Field of the Invention
The present invention relates to an anti-disaster monitoring system for monitoring abnormalities, such as fires, by receiving terminal information from fire sensors or the like by means of a receiver and by processing the received information. More particularly, the present invention pertains to an anti-disaster monitoring system in which terminal information is received from terminals which are called in sequence by a receiver which designates the address of the terminal and in which alarming or the like is performed on the basis of the received information.
2. Description of the Related Art
Conventional fire monitoring systems adopt polling in which a plurality of terminals are called in sequence by a receiver which designates the address of the terminal. That is, each of the plurality of terminals has an address which identifies that terminal. The receiver sequentially sends to the individual terminals a calling signal which designates the terminal's address. A terminal in which an abnormality, such as a fire, is detected, awaits the transmission of its address. When the address sent from the receiver coincides with the address of that terminal, the terminal transmits fire detection information or the like to the receiver during a response period which follows the call.
In such a conventional fire monitoring system which adopts the polling system, when there are few terminals, fire alarming can be made without delay. However, when the number of terminals is great, the time required to poll the terminals is proportional to the number of terminals and is thus longer. Therefore, after a fire is detected, determination and alarming of a fire by the receiver may be delayed.
When a fire transmitter is connected to a terminal, there is almost no possibility of false information.
However, in the conventional anti-disaster monitoring system of this type, operation of a fire transmitter is detected by polling, as in the aforementioned anti-disaster monitoring system, and then fire alarms are activated. As a result, after the fire transmitter is operated, activation of the alarm is delayed. This may make the fire informer (operator) anxious.
Particularly, in the case of the dual consecutive transmission collation system in which a fire is determined after fire detection information is received twice in sequence, since response signals received in response to the two calling signals are collated, activation of a fire alarm is further delayed.